Skip to content
Permalink
725bd91762
Switch branches/tags
Go to file
 
 
Cannot retrieve contributors at this time
172 lines (153 sloc) 3.38 KB
'use strict';
var utils = exports;
var BN = require('bn.js');
utils.assert = function assert(val, msg) {
if (!val)
throw new Error(msg || 'Assertion failed');
};
function toArray(msg, enc) {
if (Array.isArray(msg))
return msg.slice();
if (!msg)
return [];
var res = [];
if (typeof msg !== 'string') {
for (var i = 0; i < msg.length; i++)
res[i] = msg[i] | 0;
return res;
}
if (!enc) {
for (var i = 0; i < msg.length; i++) {
var c = msg.charCodeAt(i);
var hi = c >> 8;
var lo = c & 0xff;
if (hi)
res.push(hi, lo);
else
res.push(lo);
}
} else if (enc === 'hex') {
msg = msg.replace(/[^a-z0-9]+/ig, '');
if (msg.length % 2 !== 0)
msg = '0' + msg;
for (var i = 0; i < msg.length; i += 2)
res.push(parseInt(msg[i] + msg[i + 1], 16));
}
return res;
}
utils.toArray = toArray;
function zero2(word) {
if (word.length === 1)
return '0' + word;
else
return word;
}
utils.zero2 = zero2;
function toHex(msg) {
var res = '';
for (var i = 0; i < msg.length; i++)
res += zero2(msg[i].toString(16));
return res;
}
utils.toHex = toHex;
utils.encode = function encode(arr, enc) {
if (enc === 'hex')
return toHex(arr);
else
return arr;
};
// Represent num in a w-NAF form
function getNAF(num, w) {
var naf = [];
var ws = 1 << (w + 1);
var k = num.clone();
while (k.cmpn(1) >= 0) {
var z;
if (k.isOdd()) {
var mod = k.andln(ws - 1);
if (mod > (ws >> 1) - 1)
z = (ws >> 1) - mod;
else
z = mod;
k.isubn(z);
} else {
z = 0;
}
naf.push(z);
// Optimization, shift by word if possible
var shift = (k.cmpn(0) !== 0 && k.andln(ws - 1) === 0) ? (w + 1) : 1;
for (var i = 1; i < shift; i++)
naf.push(0);
k.iushrn(shift);
}
return naf;
}
utils.getNAF = getNAF;
// Represent k1, k2 in a Joint Sparse Form
function getJSF(k1, k2) {
var jsf = [
[],
[]
];
k1 = k1.clone();
k2 = k2.clone();
var d1 = 0;
var d2 = 0;
while (k1.cmpn(-d1) > 0 || k2.cmpn(-d2) > 0) {
// First phase
var m14 = (k1.andln(3) + d1) & 3;
var m24 = (k2.andln(3) + d2) & 3;
if (m14 === 3)
m14 = -1;
if (m24 === 3)
m24 = -1;
var u1;
if ((m14 & 1) === 0) {
u1 = 0;
} else {
var m8 = (k1.andln(7) + d1) & 7;
if ((m8 === 3 || m8 === 5) && m24 === 2)
u1 = -m14;
else
u1 = m14;
}
jsf[0].push(u1);
var u2;
if ((m24 & 1) === 0) {
u2 = 0;
} else {
var m8 = (k2.andln(7) + d2) & 7;
if ((m8 === 3 || m8 === 5) && m14 === 2)
u2 = -m24;
else
u2 = m24;
}
jsf[1].push(u2);
// Second phase
if (2 * d1 === u1 + 1)
d1 = 1 - d1;
if (2 * d2 === u2 + 1)
d2 = 1 - d2;
k1.iushrn(1);
k2.iushrn(1);
}
return jsf;
}
utils.getJSF = getJSF;
function cachedProperty(obj, name, computer) {
var key = '_' + name;
obj.prototype[name] = function cachedProperty() {
return this[key] !== undefined ? this[key] :
this[key] = computer.call(this);
};
}
utils.cachedProperty = cachedProperty;
function parseBytes(bytes) {
return typeof bytes === 'string' ? utils.toArray(bytes, 'hex') :
bytes;
}
utils.parseBytes = parseBytes;
function intFromLE(bytes) {
return new BN(bytes, 'hex', 'le');
}
utils.intFromLE = intFromLE;